Horizontal shaft impact crushers are utilized in many applications for crushing hard material, such as pieces of rock, ore, etc. A horizontal shaft impact crusher has an impeller that is made to rotate around a horizontal axis. Pieces of rock are fed towards the impeller and are struck by beater elements mounted on the impeller. The pieces of rock are disintegrated by being struck by the beater elements, and are accelerated and thrown against breaker plates, often referred to as curtains, against which further disintegration occurs. The action of the impeller thus causes the material fed to the horizontal shaft impact crusher to move freely in a crushing chamber and to be crushed upon impact against the beater elements, against the curtains, and against other pieces of material moving around at high speed in the crushing chamber.
Adjustment of the position of the curtain may be made to compensate for both curtain wear and beater element wear. Furthermore, adjustment of the position of the curtain may be made to adjust the size of the crushed material.
U.S. Pat. No. 4,017,035 discloses a horizontal shaft impact crusher which is provided with supporting hydraulic cylinders for adjusting and maintaining the position of the curtain. However, the design of the crusher described in U.S. Pat. No. 4,017,035 is considered to be complex and may be costly to manufacture and/or operate.
The present invention aims at obviating the above-mentioned disadvantages of previously known horizontal shaft impact crushers and at providing an improved crusher. Therefore, a primary object of the invention is to provide a simple and robust horizontal shaft impact crusher that allows for simple adjustment of the position of the curtain relative to the impeller, thereby controlling the wear of the curtain and impeller beater elements while minimizing cost of manufacture and operation of the crusher.